I remember that Apple's AirPort base stations used to have a DHCP "Welcome Message" feature, that would display a custom pop-up dialog when computers connected to the network. How was this accomplished?
I'm trying to duplicate this feature on a Mikrotik router (for a guest network), which means I need to know the DHCP option code that was used for this. Unfortunately, I can't find any documentation on this.
I'm sure it's some kind of standard, since it works on both Mac+Windows without any extra software, but I can't find any references to it outside of Apple's old support pages -- which don't go into technical detail about how it actually worked.
Also, Apple's newer AirPort base stations don't have this feature anymore, otherwise I could just grab a packet capture. :)
(The closest I could find was Option 56 [DHCP Message], but that seems to be something else entirely.)